Sunday, August 14, 2016

Welcome to Week 2 of the Chimp Olympics! If you missed any of the Week 1 events (or just want to re-live the glory), check them out here!Day 10:

Today's event is balancing! It may seem like having four limbs on the ground would mean that balancing is easy, but when crossing narrow log bridges, or moving on unstable lianas, it can be a real challenge. Watch these chimps balance gracefully (and sometimes not so gracefully) as they navigate some tricky spots.

Today's event is arm hanging! Suspensory (i.e. hanging) behavior makes up only a small portion of all chimpanzee locomotion: in one study suspensory locomotion accounted for less than 3% of all adult locomotion. It's more common in young chimps, and in fact there is one particular suspensory behavior only recorded for infants: arm-hang-twirling. It's a form of play where they hang by one arm and spin their body back and forth.

Today's event is charging! Like branchshaking, charging is a display done as a social signal. Superficially it resembles galloping in that it's a running motion, but the chimp is almost always piloerect (hair puffed up), and the arms and legs are held relatively stiffly. Charges are also often directed, either straight at or passing close by another individual, and accompanied by vocalizations. Charging is most often performed by adult males.

Today's event is termite fishing! Sometimes chimpanzees eat termites just by grabbing them with their hands, but they're also known to fashion tools for the job. It requires a certain amount of skill and dexterity to select the right plant, modify it to the right length, perhaps fray the end a bit for more surface area for the termites to cling to, and place it correctly for gathering termites. At some locations, chimps have been documented to use two different tools in sequence, first a sturdier one to open a mound, and then a more flexible one to collect the insects.

Today's event is object carrying! Chimps carry different objects for different reasons: they may carry food to eat somewhere else, juveniles especially may carry items to play with, and most importantly, they carry tools. Some tools that are rare or hard to acquire, like hammers for nut-cracking and particular termite-fishing tools, may be transported tens or even hundreds of meters to the site where they are used. When carrying hammers, they also often carry the nuts they intend to open. Chimps may carry items in their mouth, by using their hands or feet and modifying their gait as necessary, by placing them on their back or head, or even in their "pocket" -- a spot between their flexed thigh and lower abdomen.

Today's event is drumming! Chimpanzees make use of the large buttresses of trees to produce a low frequency noise that can be heard at least 1 km away. Drumming is sometimes part of a charging display, with the chimp charging toward a buttress, and then hitting, slapping, or kicking it, often while vocalizing. Drumming is mainly performed by adult males.

Today's event is wrestling! Just like human kids, young chimpanzees often enjoy rough-and-tumble play, including wrestling with mom, siblings, unrelated juveniles, and even adult males. Adults of both sexes may also grapple during fights, though they usually prefer to work it out without coming to blows, by using displays, vocalizations, and other social signals.

Welcome to the final day of the Chimp&See Chimp Olympics! We're glad you made it this far, and we think you and the chimps deserve a rest. Although chimpanzees can spend up to 60% of the day resting, it's not very common for us to see it on video -- immobile animals aren't very likely to trigger camera traps. Here are a few relaxing videos to end this series!

Friday, August 5, 2016

Are you excited for the Olympics? How about for the Chimp&See Chimp Olympics?! Chimpanzees can be agile, strong, and fast, and over the next few weeks, we'll be showcasing videos of them at their very best. Check back each day for a new "event", but today we have the Parade of Athletes to start us off!

Some bonus information about today's videos: chimpanzees live in communities of about 20 to about 200 individuals, but you won't ever see 200 chimps gathered at the same time! They break off into temporary parties that may be as small as a single lone individual or as large as a few dozen (and in rare cases even more), that form and reform over hours to days. Today's videos show some of the larger parties we've seen on C&S.Check back tomorrow for the first event!

Day 2:

Today's event is jumping! Since chimpanzee anatomy isn't specialized for standing upright, they often look a bit awkward when jumping and landing. It's possible for them to land both quadrupedally, putting down their hands and then their feet, or bipedally, putting down their feet first. Leaping is an uncommon behavior for chimpanzees of all ages: in one study chimpanzees spent less than 1% of their locomotion time leaping.

Day 3:
Today's event is stonethrowing! Chimpanzees may throw stones during play or during displays. In some cases, they throw stones habitually against the same trees during displays -- see PanAf's first published paper for more information. Watch the video below for some of our best stone throws!

Today's event is climbing! When chimps climb trees or vines smaller than a few inches in diameter, they grip them like a baseball bat, with the thumb opposite the fingers. They also grip with their feet, using their opposable toes for extra control and traction. For medium to large size trees, they "hug" the trunk and then basically walk up, placing each foot flat against the trunk and pushing to gain height. When returning to the ground, they usually use the same motions in reverse, but they can also "hug" the trunk and slide as seen in this video from our collaborators at the Goualougo Triangle Ape Project!

Today's event is galloping! The normal walking pattern for chimpanzees is to move each arm in time with the opposite leg, and to place them down before moving the other arm/leg. However, when they want to move faster, they can gallop instead, pushing off with both feet at once, then picking up both hands, becoming airborne for a moment!

Today's event is nut-cracking! Chimpanzees in some communities crack hard-shelled nuts to eat, which can provide them with over 3000 calories in a single day. Nut-cracking is cognitively complex, requiring knowledge of the location of nut trees, anvils, and hammers, plus the correct method for cracking. It also requires precise manipulation to correctly line up the anvil, nut, and hammer, and the physical strength to strike the nut hard enough to break it open.

Sources:Boesch, Christophe, and Hedwige Boesch-Achermann. The chimpanzees of the Taï Forest: Behavioural ecology and evolution. Oxford University Press, USA, 2000.

Day 7:

Today's event is branchshaking! Chimpanzees shake branches as a social signal. They may do it to impress a potential mate, or to intimidate a rival, or they may even direct it at another species (e.g. humans or baboons). Branchshaking displays are most often performed by adult males, but females and even juveniles perform them too.

Today's event is infant carrying! Chimpanzee newborns have a strong clinging reflex and hold tightly to the hair on mom's belly. She'll carry the infant like this on her front usually for around six to twelve months, at which point the infant starts to ride on her back instead. Infants don't all develop at the same rate, and it may be quite a number of years before mom completely stops carrying them. In fact, it may be long enough that there is a younger sibling and mom carries both at once! See if you can spot the video with a mom carrying two kids -- it's a quick one.

Today's event is crutch walking! Crutch walking is a locomotion pattern usually used on steep terrain where both hands are planted, and the body and feet are swung through the arms. It's similar to a gallop, but slower. New moms also sometimes walk this way, keeping their infant cradled in their lap.